The invention therefore relates to a mechanical adapter assembly of a transmission line for a motor vehicle comprising shafts rotatably guided by various bearings and couplings for driving said various shafts.
It is characterised in that it also comprises:                a differential carrier which is used as a crankcase containing the oil for lubricating the various bearings and couplings, the differential carrier comprising a front aperture;        a front plate integrating a pump and making it possible to close the front aperture of the differential carrier;        an attached pipe section used to supply oil from the front aperture to the differential carrier, the pipe section cooperating with additional fixtures on firstly the front plate and secondly the differential carrier.        
In other words, the mechanical adapter assembly comprises a crankcase which is open on at least one of its surfaces. This configuration makes it possible to avoid using a core and therefore facilitates cleaning and ensures that components are clean prior to being assembled.
This mechanical adapter assembly thus comprises a front plate making it possible to close the aperture of the differential carrier and also to integrate an oil pump that is rotatably driven by one of the rotating shafts inside the mechanical adapter assembly.
It also comprises an attached pipe section which also makes it possible to avoid using cores when designing the mechanical adapter assembly. This pipe section is used to supply oil inside the differential carrier from the lower part to a rear area of the differential carrier in order to lubricate the various rotating components and couplings.
Advantageously, the front plate may comprise an oil filter. In other words, when the front plate is disassembled from the differential carrier, an oil filter remains attached to the front plate and can be changed if necessary.
In practice, this oil filter may be demountable from a front surface of the front plate facing towards the outside of a mechanical adapter assembly. In other words, in this case, it is not necessary to disassemble the front plate in order to change the oil filter. This configuration is also highly attractive because it makes it possible to reduce the costs incurred by maintenance operations considerably.
In practice, the pump may be separately mounted on a surface of the front plate facing towards the inside of the mechanical adapter assembly. Thus, it is necessary to disassemble the front plate from the differential carrier in order to access the pump in order to change it or simply maintain it.
Advantageously, the pump may comprise a rotor and a stator fitted in a housing. In this case, the housing formed in the front plate acts as the case of the pump which is built when the rotor and the stator are assembled. This type of assembly avoids the use of a pre-assembled pump that forms an independent separately mounted component in the mechanical adapter assembly.
In practice, the front plate may comprise an intake area, the suction passage of which points downwards and emerges close to the bottom of the differential carrier.
In other words, a passage is used to aspirate oil which is fed into the bottom of the differential carrier by gravity. This passage emerges towards the bottom and thus has openings, the axes of revolution of which are substantially vertical. In this way, aspiration takes place as close as possible to the bottom of the differential carrier in order not to aspirate air when, in particular, the rotation speed of the various components is high.
In fact, when the rotation speed of the various components inside the mechanical adapter assembly is high, these components then constantly agitate the oil and, consequently, only a small quantity of oil remains permanently on the bottom of the mechanical adapter assembly.
The mechanical adapter assembly may comprise a system for locking the inter-axle differential. In this case the front plate may then comprise a power cylinder capable of ensuring locking of the inter-axle differential and consequently synchronising the shafts that are linked by the inter-axle differential.
In other words, in certain special cases, it is necessary to propel the vehicle by means of two synchronised powered axles. In this case, one of the shafts inside the mechanical adapter assembly is driven directly by the engine torque of the vehicle. This function is obtained by means of a power cylinder that controls the displacement of a jaw clutch which couples the differential side gear to one of the transmission output shafts of the mechanical adapter assembly.
Advantageously and in certain cases, the front plate may comprise a heat exchanger. In fact, in order to improve cooling of the oil inside the mechanical adapter assembly, it is useful to equip the front plate with a certain number of fins that act as a heat exchanger.
According to another embodiment, the front plate may comprise openings making it possible to evacuate oil and cool it in an independent heat exchanger. In this case, a certain number of hoses are used to connect the openings located on the front plate to the independent heat exchanger. This configuration makes it possible, in particular, to locate the heat exchanger in an area that is better ventilated or less exposed to soiling.
In practice, the front plate may be obtained by using a coreless moulding process. In this way, it is possible to clean every area of the part, making sure that not a single grain of sand is left behind.
In this case, a cover may be separately mounted on the front plate in order to ensure that oil is distributed to those areas that require extra oil for satisfactory lubrication. Thus, the front plate comprises an opening making it possible to provide maintenance access to the mechanical adapter assembly, this opening being closed by a cover.
Advantageously, the distinctive pipe section may comprise at least one opening making it possible to precisely lubricate a given area of the mechanical adapter assembly.
In other words, the pipe section may have a plurality of drilled holes that may or may not be fitted with nozzles or hoses making it possible to lubricate a predetermined area inside the mechanical adapter assembly. Thus the pipe section may act as a main conduit comprising several branches in order to ensure extremely precise lubrication of the various components of the mechanical adapter assembly. These various components include, in particular, the sprockets of the mechanical adapter assembly, the inter-axle differential and beatings such as the ball bearings that rotatably guide the various shafts.